The long-term goal of this research is to identify target genes regulated by quorum sensing in the human pathogen Vibrio cholerae. In particular, this study will focus on the regulation of genes required for V. cholerae to attach to surfaces and to establish microbial communities in aquatic habitats, a survival mechanism proposed to serve as a reservoir during epidemic and pandemic outbreaks. No signaling molecules have yet been identified that control V. cholerae community development. The hypothesis to be tested is that the recently described quorum sensing system of cell-to-cell communication in V. cholerae regulates expression of genes that promote development of microbial communities termed biofilms. An existing collection of quorum sensing regulatory mutants, as well as additional mutants that I will construct, will be characterized and quantified for biofilm formation. In addition, I will utilize both established and state-of-the-art techniques to identify biofilm target genes that are regulated by V. cholerae quorum sensing.